<?php

    /**
     * PHPExcel_CachedObjectStorage_Igbinary
     * Copyright (c) 2006 - 2015 PHPExcel
     * This library is free software; you can redistribute it and/or
     * modify it under the terms of the GNU Lesser General Public
     * License as published by the Free Software Foundation; either
     * version 2.1 of the License, or (at your option) any later version.
     * This library is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     * Lesser General Public License for more details.
     * You should have received a copy of the GNU Lesser General Public
     * License along with this library; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     * @category   PHPExcel
     * @package    PHPExcel_CachedObjectStorage
     * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
     * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
     * @version    ##VERSION##, ##DATE##
     */
    class PHPExcel_CachedObjectStorage_Igbinary extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache {
        /**
         * Identify whether the caching method is currently available
         * Some methods are dependent on the availability of certain extensions being enabled in the PHP build
         * @return    boolean
         */
        public static function cacheMethodIsAvailable() {
            if (!function_exists('igbinary_serialize')) {
                return false;
            }
            return true;
        }    //    function _storeData()

        /**
         * Add or Update a cell in cache identified by coordinate address
         * @param    string        $pCoord Coordinate address of the cell to update
         * @param    PHPExcel_Cell $cell   Cell to update
         * @return    PHPExcel_Cell
         * @throws    PHPExcel_Exception
         */
        public function addCacheData($pCoord, PHPExcel_Cell $cell) {
            if (($pCoord !== $this->currentObjectID) && ($this->currentObjectID !== null)) {
                $this->storeData();
            }
            $this->currentObjectID    = $pCoord;
            $this->currentObject      = $cell;
            $this->currentCellIsDirty = true;
            return $cell;
        }    //    function addCacheData()

        /**
         * Store cell data in cache for the current cell object if it's "dirty",
         *     and the 'nullify' the current cell object
         * @return    void
         * @throws    PHPExcel_Exception
         */
        protected function storeData() {
            if ($this->currentCellIsDirty && !empty($this->currentObjectID)) {
                $this->currentObject->detach();
                $this->cellCache[$this->currentObjectID] = igbinary_serialize($this->currentObject);
                $this->currentCellIsDirty                = false;
            }
            $this->currentObjectID = $this->currentObject = null;
        }    //    function getCacheData()

        /**
         * Get cell at a specific coordinate
         * @param     string $pCoord Coordinate of the cell
         * @throws     PHPExcel_Exception
         * @return     PHPExcel_Cell     Cell that was found, or null if not found
         */
        public function getCacheData($pCoord) {
            if ($pCoord === $this->currentObjectID) {
                return $this->currentObject;
            }
            $this->storeData();
            //    Check if the entry that has been requested actually exists
            if (!isset($this->cellCache[$pCoord])) {
                //    Return null if requested entry doesn't exist in cache
                return null;
            }
            //    Set current entry to the requested entry
            $this->currentObjectID = $pCoord;
            $this->currentObject   = igbinary_unserialize($this->cellCache[$pCoord]);
            //    Re-attach this as the cell's parent
            $this->currentObject->attach($this);
            //    Return requested entry
            return $this->currentObject;
        }

        /**
         * Get a list of all cell addresses currently held in cache
         * @return  string[]
         */
        public function getCellList() {
            if ($this->currentObjectID !== null) {
                $this->storeData();
            }
            return parent::getCellList();
        }    //    function unsetWorksheetCells()

        /**
         * Clear the cell collection and disconnect from our parent
         * @return    void
         */
        public function unsetWorksheetCells() {
            if (!is_null($this->currentObject)) {
                $this->currentObject->detach();
                $this->currentObject = $this->currentObjectID = null;
            }
            $this->cellCache = [];
            //    detach ourself from the worksheet, so that it can then delete this object successfully
            $this->parent = null;
        }
    }
